I am installing a raised patio using Versa Lok standard units. The wall is 2 courses high with cap. The dealer where I bought the block said most guys glue the courses instead of pins. I have installed VL before and always pinned. Would it be ok to glue if the wall is only 2 courses high? I know every type of wall needs drainage, but at just under 16" of total height could I backfill directly behind the wall with crusher run instead of #57 thus keeping my entire backfill area crusher run?